The present invention relates generally to fueling stations and, more particularly, to a breakaway device for shutting down a fueling station when a vehicle drives away with the dispensing hose of the fueling station attached thereto.
Both alternative fuels, such as liquid natural gas (LNG), and more conventional fuels, such as gasoline, are dispensed to vehicles via fueling stations. A fueling station typically includes a storage tank holding a supply of fuel, a dispensing hose with a coupling or nozzle that may be removably connected to a vehicle""s fueling port and a pump in series between the storage tank and the dispensing hose for transferring the fuel from the storage tank to the vehicle tank. In the case of LNG or other cryogenic fuels, the fueling station typically includes a conditioning arrangement so that the fuel may be warmed and/or pressurized before delivery to the vehicle. Fueling stations often feature a housing containing some of the system components with the dispensing hose attached to a side of the housing.
In nearly all fueling stations in the United States, and in many other countries, a breakaway device is installed to the dispensing hose to avoid damage to the fueling station and/or the vehicle being fueled in the event that a user drives away from the fueling station without first disconnecting the dispensing hose from the vehicle. Even with breakaway devices, such xe2x80x9cdriveawaysxe2x80x9d can result in substantial repair costs for fueling station operators. In addition, a driveaway is harmful for the environment, and possibly for individuals as well, if a large amount of fuel is spilled.
Breakaway devices are manufactured by many companies and have various constructions. Virtually all include two pieces which are intended to uncouple when a vehicle drives away from the fueling station with the dispensing hose nozzle or coupling still connected to the vehicle.
Breakaway devices are commonly installed with one piece connected to the fueling station housing and the other piece connected to the end of the dispensing system hose that is opposite the end that is equipped with the coupling or nozzle. In one example of such an arrangement, the LNG outlet of the fueling station housing is equipped with a vertical brass nipple over which the dispensing hose is placed. A chain is attached between the dispensing hose and an emergency fueling station shutoff valve. As a result, when a driveaway occurs, the dispensing hose is pulled off of the brass nipple and the chain is pulled so that the emergency valve is closed. The chain is sized so as to break in the event that the vehicle continues to drive away from the fueling station. While such an arrangement reduces system damage and stops the flow of fuel from the station, the junction between the dispensing hose and the nipple has a tendency to leak and may also bind when a driveaway occurs so that the fueling station suffers increased damage.
Improved breakaway devices that connect between and to the fueling station housing and the dispensing hose are illustrated in U.S. Pat. No. 5,520,418 to Burke and U.S. Pat. No. 6,161,872 to Vranicar. The Vranicar ""872 patent, however, is primarily directed to a device that prevents binding of the dispensing hose as it is pulled off of the nipple/male connector of the fueling station housing. As such, the breakaway arrangement of the Vranicar ""872 patent still suffers from leak and hose spill issues. The Burke ""418 patent also prevents binding of the dispensing hose and, in addition, provides an improved junction between the dispensing hose and the fueling station housing. The dispensing hose of the Burke ""418 patent includes a valve that shuts when a driveaway occurs. The valve stays with the dispensing hose after the driveaway so that the fluid within the hose does not spill onto the ground. One must contend with the fluid in the entire length of the hose when reconnecting it to the fueling station, however. In addition, while improved, the junction of the Burke ""418 patent is still susceptible to leakage issues.
Very accurate metering of cryogenic liquids during dispensing is sometimes required. The above breakaway devices all feature connectors that are attached to the fueling station housing in a vertical configuration. As a result, the hoses connected to the breakaway devices feature low points wherein liquid may be trapped after dispensing. The cryogenic liquid trapped in the hose must be vaporized and vented from the hoses before accurate dispensing may resume. A breakaway device that permits liquid in the hose to be drained after dispensing is thus desirable when accurate metering is required.
Alternative breakaway device arrangements feature couplings that are positioned in the dispensing hose a distance away from the fueling station housing. An example of such an arrangement is presented in U.S. Pat. No. 5,050,911 to Morrison. The Morrison ""911 patent illustrates a device that includes male and female members that are inserted into adjacent sections of the dispensing hose. An O-ring is positioned between the overlapping joined male and female members as is a frangible locking ring. In the event of a driveaway, the locking ring breaks so that the male member may be pulled out of the female member. As a result, one of the formerly adjacent hose sections remains connected to the fueling station housing while the other remains connected to the nozzle and vehicle. While the device of the Morrison ""911 patent is effective, its O-ring seal is susceptible to leakage. This is especially true in the case of cryogenic liquids where thermal cycling occurs at cryogenic temperatures. In addition, the device does not automatically stop the fueling station from operating in the event of a driveaway.
Several alternative breakaway devices include connectors that are integrated into dispensing hoses and that include valves which close when the hose sections that are joined by the connectors are pulled apart. More specifically, each half of the connector in such an arrangement includes a valve that activates during a driveaway so that fluid within each hose section is not spilled onto the ground. Examples of such an arrangement are presented in U.S. Pat. No. 5,297,574 to Healy; U.S. Pat. No. 5,454,602 to Anderson et al.; U.S. Pat. No. 5,564,471 to Wilder et al.; U.S. Pat. No. 5,695,221 to Sunderhaus; U.S. Pat. No. 5,570,719 to Richards et al.; and U.S. Pat. No. 6,050,297 to Ostrowski et al. The breakaway devices of these patents, however, are complicated and feature many separate parts. This increases their cost of manufacture and the chance of malfunctions.
Accordingly, it is an object of the present invention to provide a breakaway device for fueling station dispensing hoses that minimizes damage to the fueling station and vehicle in the event of a driveaway.
It is another object of the present invention to provide a breakaway device for fueling station dispensing hoses that limits the amount of fluid spilled in the event of a driveaway.
It is another object of the present invention to provide a breakaway device for fueling station hoses that permits liquid remaining in the hose after dispensing to be drained.
It is another object of the present invention to provide a breakaway device for fueling station dispensing hoses that operates in a consistent and reliable fashion.
It is still another object of the present invention to provide a breakaway device for fueling station dispensing hoses that does not leak during fuel delivery.
It is still another object of the present invention to provide a breakaway device for fueling station dispensing hoses that automatically stops the delivery of fuel by the station in the event of a driveaway.
It is still another object of the present invention to provide a breakaway device for fueling station dispensing hoses that is economical to produce.
Other objects and advantages will be apparent from the remaining portion of the specification.
The present invention is directed to a breakaway device for fueling station dispensing hoses. The breakaway device joins first and second portions of the dispensing hose where the first dispensing hose portion is connected to the fueling station and the second dispensing hose portion is connected to a coupling that connects to a vehicle during fueling. The breakaway device prevents significant damage to the station and spillage of fuel in the event of a driveaway.
The breakaway device features a pair of leg pipe members that are connected by their proximal ends to the dispensing hose portions and by their distal ends to a frangible pipe member. The leg members are oriented at an angle relative to the frangible member so that a bending moment acts on the frangible member when opposing forces exerted on the dispensing hose portions, such as during a driveaway, pull the leg members generally away from one another.
The frangible member is constructed to fracture when sum of the opposing forces pulling the proximal ends of the leg members generally away from one another exceeds a predetermined value, preferably around 400 lbs. The frangible pipe member preferably includes inner segments connected to the distal ends of the leg members with their tapered end portions secured in an abutting relationship by a surrounding frangible sleeve.
The breakaway device also includes a pneumatic line bracket attached to the proximal end of each leg member. The brackets receive a pneumatic line that provides pressurized air for opening the station dispensing valve. The pneumatic line is ruptured when the frangible member breaks and the leg members are pulled apart. As a result, the supply of pressurized air to the dispensing valve of the station is interrupted so that it closes and fuel is no longer delivered to the dispensing hose.
The following detailed description of embodiments of the invention, taken in conjunction with the appended claims and accompanying drawings, provide a more complete understanding of the nature and scope of the invention.